Wide-bandgap (WBG) semiconductor technology will largely replace silicon switching devices in the active power factor correction (PFC) circuit of a telecom power supply in the near future. Superior electrical characteristics of commercially available Gallium Nitride (GaN) devices make totem-pole PFC a clear winner over competing topologies in terms of efficiency. This thesis focuses on the development of a totem-pole PFC using state-of-the-art GaN devices for next-generation telecom power supplies. A detailed investigation of ac zero-crossings of this topology has successfully identified the rapid fluctuation in voltage across low-frequency MOSFET as the source of common-mode noise. An equivalent circuit accompanied by a set of equations correlate different circuit parameters with the noise generation. Challenges associated with current reversal near zero-crossings of a synchronous totem-pole PFC are studied and a formerly unreported source of common-mode noise generation around ac zero-crossings has been investigated in detail.